DETOUR: A Practical Backdoor Attack against Object Detection

Fuente: arXiv
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Auteurs principaux: Liu, Dazhuang, Qiao, Yanqi, Wang, Rui, Liang, Kaitai, Smaragdakis, Georgios
Format: Preprint
Publié: 2026
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author Liu, Dazhuang
Qiao, Yanqi
Wang, Rui
Liang, Kaitai
Smaragdakis, Georgios
author_facet Liu, Dazhuang
Qiao, Yanqi
Wang, Rui
Liang, Kaitai
Smaragdakis, Georgios
contents Object detection (OD) is critical to real-world vision systems, yet existing backdoor attacks on detection transformers (DETRs) for OD tasks rely on patch-wise triggers optimized at fixed locations with minimal perturbations. Such attacks overlook that backdoor triggers in the real world may appear at different sizes, fields of view (FoVs), and locations in images, while minimal perturbations are difficult for cameras to capture, limiting attack practicality. We first observe that a patch-wise trigger in DETR delivers high attack effectiveness when activating the backdoor across neighboring locations, a phenomenon we term the trigger radiating effect (TRE). Meanwhile, inserting patch-wise triggers across multiple locations synergistically enhances TRE, resulting in high attack effectiveness across images. We propose DETOUR, a practical backdoor attack by using semantic triggers that are effective in real-world object detection systems. To ensure attack practicality, we rescale trigger patterns to different sizes and insert them at various predefined locations during backdoor training, enabling the model to recognize the trigger regardless of its spatial configurations. To address FoV variations in physical deployments, we extract the trigger pattern from a real-world object (e.g., a mug) captured under multiple FoVs and inject the trigger accordingly, promoting viewpoint-invariant backdoor activation and enhancing TRE across the entire image. As a result, the backdoor can be reliably activated under diverse FoVs and spatial configurations.
format Preprint
id arxiv_https___arxiv_org_abs_2604_24599
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle DETOUR: A Practical Backdoor Attack against Object Detection
Liu, Dazhuang
Qiao, Yanqi
Wang, Rui
Liang, Kaitai
Smaragdakis, Georgios
Cryptography and Security
Object detection (OD) is critical to real-world vision systems, yet existing backdoor attacks on detection transformers (DETRs) for OD tasks rely on patch-wise triggers optimized at fixed locations with minimal perturbations. Such attacks overlook that backdoor triggers in the real world may appear at different sizes, fields of view (FoVs), and locations in images, while minimal perturbations are difficult for cameras to capture, limiting attack practicality. We first observe that a patch-wise trigger in DETR delivers high attack effectiveness when activating the backdoor across neighboring locations, a phenomenon we term the trigger radiating effect (TRE). Meanwhile, inserting patch-wise triggers across multiple locations synergistically enhances TRE, resulting in high attack effectiveness across images. We propose DETOUR, a practical backdoor attack by using semantic triggers that are effective in real-world object detection systems. To ensure attack practicality, we rescale trigger patterns to different sizes and insert them at various predefined locations during backdoor training, enabling the model to recognize the trigger regardless of its spatial configurations. To address FoV variations in physical deployments, we extract the trigger pattern from a real-world object (e.g., a mug) captured under multiple FoVs and inject the trigger accordingly, promoting viewpoint-invariant backdoor activation and enhancing TRE across the entire image. As a result, the backdoor can be reliably activated under diverse FoVs and spatial configurations.
title DETOUR: A Practical Backdoor Attack against Object Detection
topic Cryptography and Security
url https://arxiv.org/abs/2604.24599